A Lipopolysaccharide Synthesis Gene rfaD from Mesorhizobium huakuii Is Involved in Nodule Development and Symbiotic Nitrogen Fixation.
A Lipopolysaccharide Synthesis Gene rfaD from Mesorhizobium huakuii Is Involved in Nodule Development and Symbiotic Nitrogen Fixation.
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DOI：
10.3390/microorganisms11010059
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发表时间：
2022-12-25
期刊：
影响因子：
4.5
通讯作者：
Xie, Xianan
中科院分区：
文献类型：
--
作者：
Liu, Yuan;Lin, Ye;Guan, Ning;Song, Yuting;Li, Youguo;Xie, Xianan
关键词：
根瘤菌脂多糖（LPS）是革兰氏阴性菌细胞壁的重要组成部分，作为根瘤菌表面的信号分子，参与根瘤菌与豆科植物相互作用的共生过程。在本研究中，我们构建了Mesorhizobium huakuii 7653R ADP-L-甘油-D-甘露庚糖基-6-外切异构酶（rfaD）的缺失突变体和功能互补菌株。结果表明，rfaD 的缺失并不影响 7653R 的自由生长速率，但确实影响了 LPS 的合成，并增加了对非生物胁迫的敏感性。 rfaD启动子-GUS报告基因检测显示该基因主要表达于成熟结节的感染区。 rfaD突变体在与寄主紫云英共生期间，根瘤形成被延迟。共生表型分析表明，接种rfaD突变株后，中华A. sinicus根瘤失去了共生固氮能力。总之，我们的结果表明，7653R rfaD 基因在涉及根瘤菌和中华曲霉之间共生相互作用的脂多糖合成中起着至关重要的作用。这项研究还为根瘤菌调节自身基因表达和细胞壁成分从而使豆类结瘤的分子机制提供了新的见解。
Rhizobium lipopolysaccharide (LPS) is an important component of the cell wall of gram-negative bacteria and serves as a signal molecule on the surface of rhizobia, participating in the symbiosis during rhizobia–legume interaction. In this study, we constructed a deletion mutant of ADP-L-glycerol-D-mannoheptosyl-6-exoisomerase (rfaD) of Mesorhizobium huakuii 7653R and a functional complementary strain. The results showed that the deletion of rfaD did not affect the free-living growth rate of 7653R, but that it did affect the LPS synthesis and that it increased sensitivity to abiotic stresses. The rfaD promoter-GUS reporter assay showed that the gene was mainly expressed in the infection zone of the mature nodules. The root nodules formation of the rfaD mutant was delayed during symbiosis with the host plant of Astragalus sinicus. The symbiotic phenotype analyses showed that the nodules of A. sinicus lost symbiotic nitrogen fixation ability, when inoculated with the rfaD mutant strain. In conclusion, our results reveal that the 7653R rfaD gene plays a crucial role in the LPS synthesis involved in the symbiotic interaction between rhizobia and A. sinicus. This study also provides new insights into the molecular mechanisms by which the rhizobia regulate their own gene expression and cell wall components enabling nodulation in legumes.
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影响因子：
9.4
作者：
Li, Yixing;Zhou, Lei;Zhou, Junchu
通讯作者：
Zhou, Junchu
影响因子：
9.4
作者：
Albus, U;Baier, R;Niehaus, K
通讯作者：
Niehaus, K
影响因子：
3.2
作者：
Kneidinger, B;Marolda, C;Messner, P
通讯作者：
Messner, P
影响因子：
3.2
作者：
Loutet, SA;Flannagan, RS;Valvano, MA
通讯作者：
Valvano, MA
影响因子：
7.3
作者：
Hastwell, April H.;Corcilius, Leo;Ferguson, Brett J.
通讯作者：
Ferguson, Brett J.